Automatic advancing-gear.



- JOHN E. CROWELL, 0F UNION COUNTY, NORTH CAROLINA.

ressens.;

To all whom t may concern:

. Be it known that l, JOHN E. CRowELL, a citizen of the -lUnited States, and a resident of Union county, in the State of North Carolina, have inventedV a new and useful mprovement in Automatic' Advancing- Gear, of which the following is a specification.

I My invention relates to improvements in internal combustion engines, and more particularly to cam shaft gears and it consists in the constructions, combinations, and arrangements herein described and claimed.

An object of my invention is to provide a gear for the cam shaft of an internal combustion engine whereby the valves may be prematurely opened when the engine speeds up, in order to derive the full benefit of the power of the engine.

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawings formmg a part thereof, and in which:

Figure 1 is a diagrammatic ,vertical cross section of an engine illustrating the action of my devie on the exhaust valve of the Y engine.

Fig. 2 is a crosssection on the line 2-2of Fig. 1.

Fig. 3 is an elevationfof the device show- -ing the parts in a normal position.

Fig. 4 is a similar view showing the parts as positioned in Fig. 1.

Fig. 5 is a detail perspective view of one of the centrifugal members.

` By reference to Fig. 1 it will be observed that my device is embodied in an internal combustion engine ofl the usual type, which includes the crank shaft 1 and a cam shaft 2. The cam shaftcarries a cam 3 with which the roller 4 of the exhaust valve stem 5 engages. 1t may bepstated that in some engines of modern construction, the exhaust and inlet valve cams are carried by one shaft as shown in Fig. 1 of the drawings. The device is, however, applicable to motors having separateinlet and exhaust valve opcam shafts, and in such instances one o the cam shaft gears is mounted on each shaft.

Mounted on the crank shaft 1 is a crank 6 with which the connecting rod 7 is joined.

The connecting rod 7 carries the working piston 8 which reciprocates in the cylinder '9' of the engine. Carried by the crank `shaft 1- is a pinion 10. The pinion. 10 meshes Specication of Letters Patent.

aurona'ric @venerare-enen.

Patented elnne 12, 191'?.

Application led 1' uly 15, 1916. Serial No. 109,486.

with the rim gear 11 which comprises an essential part of my invention. Secured tol the end of the cam shaft 2 by screw bolts 12 is a cover plate 13. The cover plate 13 has an annular flange 14 forming'a shoulder 15 in which the rim gear 11 is supported. By reference to Figs. 1, 2 and 4, it will be observed that a pair of centrifugal members 16 and 17 respectively, are mounted on the cover plate 13.

The centrifugal members 16 and 17 are pivotally mounted on the cover plate 13 by screw studs 18 which support the centrifugal members. Each of the centrifugal members 16 and 17 is provided with a flange A16a and 17a, a shoulder 16b and 17b being formed at the juncture of the respective flanges with the bodies of the centrifugal members. The remaining portion of the rim gear 11 rests in the respective shoulders 16b and 17b as shown in Fig. 2, thereby supporting the rim gear 11 equally on the bodies of the centrifugal members and the body of the cover plate 13. The centrifugal members 16 and 17 are adapted to swing outwardly when the speed of cam shaft 2 becomes excessive, as will presently Ebe more fully explained.

The centrifugal members 16 and 17 are provided with'notches 16e and 17cr at places approximately diametrically opposite to the fulcrum studs 18. The rim gear '11 is provided with single teeth 20 at diametrically opposite points Aand these teeth 20 loosely engage the notches 16c and 17c as shown in Figs. 3 and 4.4 The purpose of the notches and the teeth 2O is to obviate any undue movement of the centrifugal members 16 and 17 when they are in an extended position, as shown in Fig. 4.

Secured to the edge of each of the centrifugal members 16 and f1?, is a leaf spring 21. The leaf Ysprin 21 is mounted in a suitable recess22 in't e edge of each 'of these` Mit lill@ yzo 'Vee

lthe exhaust cam 3 willbe in such a position as to begin to operate the exhaust valve 5.

The purpose of this setting is to openthe exhaustyalve early enou h when the engine is traveling at fast speergl.

With the automatic advancing gear attached, when the engine is running at slow speed, the inlet valves are caused to open late and in eifect produce a greater suction.

I have also observed in actual practice that the engine is capable of being cranked more easily. This is so because of the fact that the valves are set in a retarded position in the lirst instance, as previously explained. llt therefore follows as above stated, that the piston will traverse a greater distance down the cylinder before the inlet valve will open. A greater suction is thereby caused, serving to draw in a greater volume of gas.

in assembling an engine embodying m invention, l set the crank 6 at the point in Fig. l, which is approximately oneeighth of an inch of the extremity of the outward or exhaust stroke of the piston, while the cam 3 is set so the valve will begin to open. The purpose of this arrangement will presently be made clear. l

.Let it now be assumed that the engine speeds up. The centrifugal members 16 and 17 will begin to move outwardly in the direction of the arrows c in Fig. 3. ln moving outward, the centrifugal members 1G and 17 will rotate on the studs 18 in a counter-clockwise direction, indicated by arrow d in` Fig. 3, until the positon is reached as shown in Fig. 4. The centrifugal members 16 and 17 are fully extended in this position. In having moved from the posltion shown in Fig. 3 to that shown in Fig. ll, the fulcrum pins carried the cover plate 13 in the same direction, since, as previously stated and shown in the drawing, the cover plate and the centrifugal members are connected thereby. Since the action just exlained was accomplished by the centrifugal orce generated by the accelerated speed of the cam shaft 2, it follows that since the coverplate 13 is joined with the cam shaft 2, the cam shaft 2 will be slightly advanced. Assuming the crank 6 to be at the point e in Fi 1 and the accelerated speedof the cam s aft occurring at this time, the cam 3 will be moved from the dotted osition shown in Fig. 1 to the fuii line position indicated when the exhaust valve `5 will be near-)pee My invention is also adapted for driving magneto shafts. ln the usual construction of magnetos, the spark timing mechanism is mounted on the magneto casing, and an operating rod is conducted to the spark lever on the steeringV wheel. The spark is advanced and retarded by moving the spark lever back and forth. When my device is applied, however, the spark lever and connecting rod are dispensed with. The cover plate 13 with its associated members is then secured to the end of the magneto shaft, similarly-as shown in Fig. 2. rihe timing of the spark is then varied by the action of the centrifugal members 16 and 17 by allow- -ing the spark to occur earlier or later depending on the speed of the engine, and the position of the magneto armature is not required to be changed with relation to the magnetic pole pieces.

While the constructions and arrangements l described are those of a preferred form, ob-

viously various modifications may be made without departing from the spirit of the invention or the scope of the claims,

l claim l 1. ln an internal combustion engine, the combination with the crank shaft'and the cam shaft for operating the valves, of gearing connecting the two shafts and including' a rim gear, a plate fast with the cam shaft to rotateptherewith, and having the rim gear mounted thereon, and centrifugally operated members pivoted at one of their ends to the said plate, and having their opposite ends loosely connected with the rim gear, said members acting to'advance the cam shaft in the direction of its rotation upon acceleration of the speed of the engine;

2. lln combination, a rotary driving member, a rotary driven member geared to the rotary driving member, a rotary valve operating-member mounted co-axially with the rotary driven member, a cover plate attached to the rotary valve operating member and having the said rotary driven member mounted thereon, and centrifu ally operated means mounted on the cover p ate and formin direct connecting means between the said cover plate and rotary driven member for advancing the latter.

3. in combination, a rotary drivingfmember, a rotary driven member geared to the rotary driving member, a rotary valve op- 

